PROLOG This manual page is part of the POSIX Programmer
s Manual. The Linux implementation of this interface may
differ (consult the corresponding Linux manual page for
details of Linux behavior), or the interface may not be
implemented on Linux.

DESCRIPTION These functions shall compute the complex
arc cosine of z, with branch cuts outside the interval [-1,
+1] along the real axis.

RETURN VALUE These functions shall return the complex
arc cosine value, in the range of a strip mathematically
unbounded along the imaginary axis and in the interval [0,
pi] along the real axis.

ERRORS No errors are defined.

The following sections are informative.

EXAMPLES None.

APPLICATION USAGE None.

RATIONALE None.

FUTURE DIRECTIONS None.

SEE ALSO ccos(), the Base Definitions volume of IEEE Std
1003.1-2001, <com- plex.h>

COPYRIGHT Portions of this text are reprinted and
reproduced in electronic form from IEEE Std 1003.1, 2003
Edition, Standard for Information Technology -- Portable
Operating System Interface (POSIX), The Open Group Base
Specifications Issue 6, Copyright (C) 2001-2003 by the
Institute of Electrical and Electronics Engineers, Inc and
The Open Group. In the event of any discrepancy between this
version and the original IEEE and The Open Group Standard,
the original IEEE and The Open Group Standard is the referee
document. The original Standard can be obtained online at
http://www.opengroup.org/unix/online.html .